Horse Equine Herpesvirus and Biosecurity

Equine herpesvirus causes neurological disease outbreaks that can devastate competition horses and breeding operations, making strict biosecurity protocols essential for prevention.

Key Facts

EHV-1 causes respiratory disease, abortion storms, and neurological disease (EHM) in horses
The neuropathogenic strain of EHV-1 causes equine herpesvirus myeloencephalopathy
EHM outbreaks at competition venues have resulted in mass quarantines
The virus spreads through nasal secretions and direct contact
No vaccine reliably prevents neurological disease though some reduce respiratory severity
Temperature monitoring can detect infection before obvious neurological signs appear
Affected horses develop incoordination, urinary incontinence, and may become recumbent
Quarantine periods of 28 days are typically required following outbreak exposure

Welfare Considerations

EHM-affected horses experience devastating neurological deterioration - from incoordination to complete inability to stand within days. Recumbent horses cannot rise without assistance and risk aspiration pneumonia and pressure sores. Abortion in late pregnancy causes physical distress for mares and the loss of months of pregnancy investment. The rapid spread in competition settings can expose hundreds of horses before an outbreak is recognized. Strict biosecurity - temperature monitoring and rapid isolation - is the primary welfare protection.

What You Can Do

Monitor horse temperatures daily during competition season as an early outbreak signal
Implement strict biosecurity when returning horses from competitions
Vaccinate horses against EHV-1 and EHV-4 respiratory strains on current schedules
Report suspected EHM cases to your veterinarian immediately
Support EHV research into more effective vaccines preventing neurological disease